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Alcohol Use During Smoking Cessation Predicted Failure, but Marijuana Use Did Not

Among 199 smokers in a cessation program, even low-to-moderate alcohol use during treatment predicted relapse at all follow-up points, while marijuana use neither at baseline nor during treatment predicted smoking outcomes.

Humfleet, G et al.·Addictive behaviors·1999·Moderate EvidenceProspective Cohort
Quitting (221)Addiction (1380)
RTHC-00081Prospective CohortModerate Evidence1999RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Prospective Cohort
Evidence
Moderate Evidence
Sample
N=199

What This Study Found

Researchers examined how alcohol and drug histories affected smoking cessation in 199 clinic patients. Nearly a quarter (23%) had a history of alcohol or drug problems, 79% used alcohol, and 21% used marijuana during treatment.

History of substance abuse did not predict cessation outcomes. But current substance use patterns diverged sharply. Alcohol use, even at low-to-moderate levels, predicted smoking at every follow-up assessment. Participants who used any alcohol during treatment had significantly lower quit rates.

Marijuana use told a different story. Neither baseline marijuana use nor marijuana use during treatment predicted smoking outcomes. Marijuana users quit smoking at the same rates as non-marijuana-users.

This finding was surprising given previous research linking marijuana to smoking cessation failure, suggesting the relationship may be more nuanced than earlier studies indicated.

Key Numbers

199 participants. 23% had alcohol/drug problem history. 79% used alcohol. 21% used marijuana during treatment. Alcohol predicted smoking at all follow-up points. Marijuana predicted nothing.

How They Did This

Prospective study of 199 smokers in a cessation clinic. History of alcohol/drug problems, current alcohol use, and current marijuana use were assessed. Abstinence was measured at multiple follow-up points.

Why This Research Matters

This study challenged the assumption that marijuana use necessarily undermines tobacco cessation. By separating alcohol and marijuana effects, it showed that alcohol was the primary substance-use barrier to quitting smoking, while marijuana was neutral.

The Bigger Picture

This finding contrasted with a 1994 study showing marijuana use halved tobacco cessation success. The discrepancy likely reflects different populations, settings, and levels of marijuana use, illustrating how context matters when studying substance interactions.

What This Study Doesn't Tell Us

Relatively small sample (199). Marijuana use was self-reported and the 21% rate may reflect varying use levels. The study may not have been powered to detect smaller marijuana effects. The clinic population may not represent all smokers.

Questions This Raises

  • ?Why did this study find no marijuana effect while an earlier study found a strong one?
  • ?Does the level of marijuana use matter (occasional versus daily)?
  • ?Could marijuana be used as a substitute to reduce cigarette cravings?

Trust & Context

Key Stat:
Marijuana use did not predict smoking cessation failure, but alcohol use did
Evidence Grade:
A prospective clinic study with multiple follow-up assessments. Good design but modest sample size and potential for unmeasured confounders.
Study Age:
Published in 1999. Research on cannabis-tobacco interactions continues with mixed findings across different populations.
Original Title:
History of alcohol or drug problems, current use of alcohol or marijuana, and success in quitting smoking.
Published In:
Addictive behaviors, 24(1), 149-54 (1999)
Database ID:
RTHC-00081

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Enrolls participants and follows them forward in time.

What do these levels mean? →

Frequently Asked Questions

Does marijuana use make it harder to quit smoking?

In this study, no. Marijuana use at baseline and during treatment did not predict smoking cessation outcomes. Alcohol use, by contrast, predicted failure at every follow-up point.

Does having a drug history matter?

No. A history of alcohol or drug problems did not predict cessation outcomes. What mattered was current substance use during the quit attempt.

Read More on RethinkTHC

Cite This Study

RTHC-00081·https://rethinkthc.com/research/RTHC-00081

APA

Humfleet, G; Muñoz, R; Sees, K; Reus, V; Hall, S. (1999). History of alcohol or drug problems, current use of alcohol or marijuana, and success in quitting smoking.. Addictive behaviors, 24(1), 149-54.

MLA

Humfleet, G, et al. "History of alcohol or drug problems, current use of alcohol or marijuana, and success in quitting smoking.." Addictive behaviors, 1999.

RethinkTHC

RethinkTHC Research Database. "History of alcohol or drug problems, current use of alcohol ..." RTHC-00081. Retrieved from https://rethinkthc.com/research/humfleet-1999-history-of-alcohol-or

Access the Original Study

View on PubMed

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.

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